Google has warned site owners that its Chrome browser would drop the hammer by blocking all ads if the website harbored what the search giant called “abusive experiences”.

“Starting in December 2018, Chrome 71 will remove all ads on the small number of sites with persistent abusive experiences (emphasis added),” wrote Vivek Sekhar, a product manager with Google, in a post to a company blog.

Sekhar’s threat did not come out of the blue: Google gave Chrome leave to take on abusive experiences before. The browser, which has long blocked pop-up ads and more recently restricted video auto-play, this summer stopped unauthorised redirections – where clicking a link opens the destination in a new tab but nefariously opens an unwanted page in the former active tab – with July’s Chrome 68. (It was unclear whether this has been enabled by default; to switch it on may still require a trip to chrome://flags and toggling the Framebusting requires same-origin or a user gesture option.)

Google spelled out other abusive experiences in a help document that referred to such malfeasances as ads with misleading branding and phishing attempts to fake ‘play’ buttons and phony system messages. All had some connection to online advertisements that Google classified as dodgy.

Sekhar cited the abuses as the reason for Chrome lowering the boom. “More than half of these abusive experiences are not blocked by our current set of protections, and nearly all involve harmful or misleading ads,” he said, implying that Google had to do more.

That would be shutting off the financial faucet of sites by scrubbing all ads from their pages. Google did not elaborate, saying only that sites with “persistent” abuses – with that key word left undefined – would be targeted.

It was unclear whether user complaints would factor into Google’s decision to take aim at a site, or if the judgment was made programmatically. Admins were encouraged to run Google’s Abusive Experiences Report to see what abusive experiences their sites contain, if any.

“Site owners will have a 30-day window to fix experiences flagged by the Report before Chrome removes ads,” Sekhar said.

Google is able to throw its weight around like this – deciding what is, and is not, acceptable on the Web – because of the immense power it holds with Chrome. Because a landslide majority of users run Chrome – analytics vendor Net Applications put Chrome’s user share for October at a record 66.4% on the desktop, 63% on mobile – when Google says “jump,” websites must reply “how high?” To do otherwise would be business suicide.

Chrome 71, which will enforce the new mandate, is slated to release the week of 8 December.